Fukushima Agricultural Technology Center

Kōriyama, Japan

Fukushima Agricultural Technology Center

Kōriyama, Japan

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Fujimura S.,Fukushima Agricultural Technology Center | Ishikawa J.,Japan National Agriculture and Food Research Organization | Sakuma Y.,Fukushima Agricultural Technology Center | Saito T.,Fukushima Agricultural Technology Center | And 2 more authors.
Journal of Environmental Radioactivity | Year: 2014

After the accident at the Fukushima Dai-ichi Nuclear Power Plant owned by Tokyo Electric Power Company on 11 March 2011, potassium was applied to fields in the Tohoku and Kanto areas of Japan to reduce radiocesium uptake by crops. Despite the intense studies relating to the effect of potassium application on availability of radiocesium in the soil, physiological changes of radiocesium uptake by crops in response to K+ concentration around roots remains elusive. In the present study, we developed physiological models describing the effect of K+ on the uptake of radiocesium by rice. Two Cs+:K+ competition models were evaluated using a wide range of data obtained from pot and field experiments: the model assuming a uniformity in the gene expression of K+ transporter (Model I) and the model assuming the increase in the gene expression of K+ transporter in response to K+ concentration below threshold (Model II). The root-mean-square deviation between the measured and estimated values was larger in Model I than in Model II. Residuals were positively correlated with K+ in Model I but showed no deflection in Model II. These results indicate that Model II explains the effect of K+ on the uptake of radiocesium better than Model I. Model II may provide the appropriate countermeasures in inhibiting the transfer of radiocesium from soil to crop. The effect of changes in the variables in Model II on the relationship between available K+ in soil and 137Cs uptake by plant was simulated. An increase in available 137Cs+ in soil enhanced the response of 137Cs uptake to K+. The effects of Michaelis-Menten constant for Cs+ were the inverse of the 137Cs+ effect. The effect of Michaelis-Menten constant for K+ showed the same tendency as that of 137Cs+, but the effect was much less than that of 137Cs+. An increase in the threshold of K+ below which the gene expression of K+ transporter increases enhanced the response of 137Cs uptake to K+ in the high-K+ range. © 2014 Elsevier Ltd.


Tsuji H.,Japan National Institute of Advanced Industrial Science and Technology | Kondo Y.,Japan Vilene Company | Suzuki Y.,Fukushima Agricultural Technology Center | Yasutaka T.,Japan National Institute of Advanced Industrial Science and Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2014

A method for the rapid and simultaneous monitoring of particulate and dissolved 137Cs concentration in water was developed. This method uses pleated polypropylene nonwoven fabric filter to collect particulate radiocesium, and nonwoven fabric impregnated with Prussian blue (PB) to absorb dissolved radiocesium. The fabric was placed into cylindrical plastic cartridges (SS-cartridge and PB-cartridge). Traditional monitoring methods, such as evaporative concentration, often require time for pre-processing. However, this method described requires much less pre-processing time before the detection. Experiments conducted with simulated river water demonstrated that almost all of the suspended solids weight was collected in the SS-cartridge, and that more than 92 % of dissolved 137Cs was absorbed onto the two PB-cartridges by 2.5 L/min flow rate when the range of the pH was 6-8. This device was applied to monitor Abukuma River water at two locations and the results were compared with those obtained using the filtrating and evaporative concentration method. The suspended solids concentration in river water, calculated by weight gain of the SS-cartridge and by sediment weight after filtration with a 0.45-μm membrane filter, agreed well. The radioactivity of the particulate and dissolved 137Cs also agreed well in one of the two replications of this method. In addition, the required time for pre-processing was reduced by 60 times that by filtrating and evaporative concentration method. This method can separately collect and concentrate particulate and dissolved radiocesium rapidly and simultaneously in the field. © 2013 Akadémiai Kiadó, Budapest, Hungary.


Parajuli D.,Japan National Institute of Advanced Industrial Science and Technology | Takahashi A.,Japan National Institute of Advanced Industrial Science and Technology | Tanaka H.,Japan National Institute of Advanced Industrial Science and Technology | Sato M.,Fukushima Agricultural Technology Center | And 3 more authors.
Journal of Environmental Radioactivity | Year: 2015

Cesium extraction behavior of brown forest type soil collected from paddy fields in Fukushima nuclear accident affected areas was studied. In nitric acid or sulfuric acid solutions at elevated temperature, the concentration of Cs in soil available for extraction, m0, has been estimated on the basis of modified canonical equation and the equations derived from assumed equilibria. With the variation in temperature, mixing time, and soil to solvent ratio, the observed m0 values in 0.5M acid solution ranged between 1.5 and 2.9mg cesium per kilogram of soil. By increasing the acid concentration to 3M, the value of m0 could be sharply increased to 5.1mg/kg even at 95°C. This variation in the extractable concentration of cesium with the parameters signifies the existence of different binding sites in the soil matrix. The results observed for uncontaminated sample could be reproduced with the radioactive cesium contaminated sample belonging to the same soil group. © 2014 Elsevier Ltd.


Fumoto T.,Japan National Institute for Agro - Environmental Sciences | Yanagihara T.,Hokkaido Kamikawa Agricultural Experiment Station | Saito T.,Fukushima Agricultural Technology Center | Yagi K.,Japan National Institute for Agro - Environmental Sciences
Global Change Biology | Year: 2010

Rice production is a substantial source of atmospheric CH4, which is second only to CO2 as a contributor to global warming. Since CH4 is produced in anaerobic soil environments, water management is expected to be a practical measure to mitigate CH4 emissions. In this study, we used a process-based biogeochemistry model (DNDC-Rice) to assess the CH4 mitigation potentials of alternative water regimes (AWR) for rice fields at a regional scale. Before regional application, we tested DNDC-Rice using site-scale data from three rice fields in Japan with different water regimes. The observed CH4 emissions were reduced by drainage of the fields, but were enhanced by organic amendments. DNDC-Rice gave acceptable predictions of variation in daily CH4 fluxes and seasonal CH4 emissions due to changes in the water regime. For regional application, we constructed a GIS database at a 1 × 1 km mesh scale that contained data on rice field area, soil properties, daily weather, and farming management of each cell in the mesh, covering 3.2% of the rice fields in Japan's Hokkaido region. We ran DNDC-Rice to simulate CH4 emissions under five simulated water regimes: the conventional water regime and four AWR scenarios with gradually increasing drainage. We found that AWR can reduce CH4 emission by up to 41% compared with the emission under conventional water regime. Including the changes in CO2 and nitrous oxide emissions, potential mitigation of greenhouse gas (GHG) was 2.6 Mg CO2 Eq. ha-1 yr-1. If this estimate is expanded to Japan's total rice fields, expected GHG mitigation is 4.3 Tg CO2 Eq. yr-1, which accounts for 0.32% of total GHG emissions from Japan. For a reliable national-scale assessment, however, databases on soil, weather, and farming management must be constructed at a national scale, as these factors are widely variable between regions in Japan. © 2009 Blackwell Publishing Ltd.


Takeda A.,Japan Institute for Environmental Sciences | Tsukada H.,Japan Institute for Environmental Sciences | Tsukada H.,Fukushima University | Yamaguchi N.,Japan National Institute for Agro - Environmental Sciences | And 4 more authors.
Journal of Environmental Radioactivity | Year: 2014

The concentration of radiocesium (134Cs and 137Cs) in agricultural fields around Fukushima Dai-ichi Nuclear Power Plant (FDNPP) was elevated after the accident in March 2011. Evaluation of soil properties that influence phytoavailability of radiocesium is important for optimal soil management to minimize radiocesium transfer to crops. In this study, soybean grain and soil samples (0-15cm) were collected from 46 locations in Fukushima Prefecture in 2011, and 137Cs concentrations were measured. 137Cs concentration ranges were 11-329Bqkg-1-dry in soybean grain samples, and 0.29-2.49kBqkg-1-dry in soil samples. The radiocesium interception potential (RIP) values in the soil samples ranged from 0.30 to 8.61molkg-1. RIP negatively correlated with total carbon content and oxalate-extractable Si and Al+ 1/2 Fe in the soils, suggesting that soils rich in organic matter and poorly crystalline clays tended to have lower RIP in this region. The soil-to-plant transfer factor for 137Cs, analyzed in relation with various soil characteristics, varied by two orders of magnitude and was significantly negatively correlated with RIP and exchangeable K concentration in soil. The results show that RIP is useful for evaluating the efficiency of radiocesium transfer from soil to plants in this region. © 2014 Elsevier Ltd.


Saito T.,Fukushima Agricultural Technology Center | Saito T.,Tokyo University of Technology | Otani T.,Japan National Institute for Agro - Environmental Sciences | Seike N.,Japan National Institute for Agro - Environmental Sciences | Okazaki M.,Tokyo University of Technology
Soil Science and Plant Nutrition | Year: 2015

Dieldrin, an insecticide that is considered a persistent organic pollutant, remains in the soil for a long time after application. In recent years, dieldrin has been detected in cucumber (Cucumis sativus L.) fruits produced in some areas at concentrations exceeding the tolerance limit in Japan. Thus, we compared dieldrin residues in 19 vegetable crops produced in a dieldrin-contaminated field. Since dieldrin concentrations in the soil of each crop plot differed about 2-fold, we used the bioconcentration factor to compare the degree of dieldrin residue contamination among crops. The bioconcentration factors of Cucurbitaceae crops were much higher than those of non-Cucurbitaceae crops. Among non-Cucurbitaceae crops, the bioconcentration factors of komatsunas (Brassica campestris var. perviridis), Japanese radishes (Raphanus sativus L.), carrots (Dancus carota L.), and potatoes (Solanum tuberosum L.) were relatively high. In these Cucurbitaceae plants, dieldrin was not accumulated in particular parts or organs. On the other hand, in carrot roots, Japanese radish roots, and potato tubers, higher amounts of dieldrin were detected in the skin, small amounts were found in the outer flesh, and none was detected in the inner flesh, core, or leaf. To select the alternative crops to grow in dieldrin-contaminated fields, we propose to use the ‘‘tolerance limit over factor’’, which we calculated by dividing the bioconcentration factor by the tolerance limit of the crop. The tolerance limit over factor of Cucurbitaceae crops was higher than that of non-Cucurbitaceae crops. In Cucurbitaceae, the tolerance limit over factor of cucumbers was much higher than that of zucchini and pumpkins, though the bioconcentration factors of these cucurbits were nearly the same. In non-Cucurbitaceae crops, the tolerance limit over factors of komatsunas, Japanese radishes, and potatoes were similar in value to those of zucchini (Cucurbita pepo L.) and pumpkins (Cucurbita maxima Duch.). By considering the tolerance limit over factor values, we propose that Cucurbitaceae crops, root crops (especially Japanese radish), tubers (especially potato), and leafy vegetables (especially komatsuna), in which dieldrin tolerance limits are set at low concentrations, are not appropriate for cultivation in dieldrin-contaminated fields. © 2012 Japanese Society of Soil Science and Plant Nutrition.


Tanaka K.,Hiroshima University | Takahashi Y.,Hiroshima University | Sakaguchi A.,Hiroshima University | Umeo M.,Hiroshima University | And 4 more authors.
Geochemical Journal | Year: 2012

Vertical profiles of iodine-131 and cesium-137 emitted from the Fukushima Daiichi Nuclear Power Station were determined in soil core samples collected in Fukushima prefecture. The profiles showed that more than 76% of the radionuclides were retained within 5 cm of the surface. Leaching experiments showed that cesium was strongly bound to soil particles which could not be leached with 2 M HCl, while more than 40% of iodine was incorporated into humic substances. © 2012 by The Geochemical Society of Japan.


Ohno T.,Gakushuin University | Muramatsu Y.,Gakushuin University | Miura Y.,Fukushima Prefecture Government | Oda K.,Gakushuin University | And 5 more authors.
Geochemical Journal | Year: 2012

In order to understand the behavior of radionuclides released from the Fukushima Daiichi nuclear power plant, the depth distributions of radiocesium and radioiodine were investigated in a wheat field, a rice paddy, an orchard, and a cedar forest in Koriyama, Fukushima Prefecture. Our results demonstrate that, following the nuclear power plant disaster, more than 90% of the radionuclides were distributed in the upper 6 cm of the soil column in the wheat field and within 4 cm of the surface in the rice paddy, orchard, and cedar forest. According to the measurement of radionuclides in the three adjacent agricultural fields, the variation of deposition densities in the wheat field was smaller than that of the orchard and rice paddy, suggesting that the low permeability of the orchard and paddy soils may cause horizontal migration of radionuclides during the initial deposition. This result indicates that the deposition densities in the wheat field should be appropriate for estimating the amount of fallout in the area. The deposition densities of 134Cs, 137Cs, and 131I in this area were estimated to be 512 ± 76 (SD, η = 5), 522 ± 80 (SD, η = 5), and 608 ± 79 (SD, η = 5) kBq/m2 (decay corrected to April 1, 2011), respectively. A comparison of the deposition density between the wheat field and the cedar forest suggests that more than half of the radionuclides are distributed in the tree canopies of the evergreen forestland. © 2012 by The Geochemical Society of Japan.


Fujimura S.,Fukushima Agricultural Technology Center | Yoshioka K.,Fukushima Agricultural Technology Center | Saito T.,Fukushima Agricultural Technology Center | Sato M.,Fukushima Agricultural Technology Center | And 2 more authors.
Plant Production Science | Year: 2013

Radionuclides were released into the environment as a consequence of the Fukushima Daiichi Nuclear Power Plant accident that occurred on 11 March 2011. Radiocesium at an abnormal concentration was detected in brown rice produced in paddy felds located in northern part of Fukushima Prefecture. We examined several hypotheses that could potentially explain the excessive radiocesium level in brown rice in some of the paddy fields, including (i) low exchangeable potassium content of the soil, (ii) low sorption sites for cesium (Cs) in the soil, and (iii) radiocesium enrichment of water that is flowing into the paddy fields from surrounding forests. The results of experiments using pots with contaminated soil indicated that the concentration of radiocesium in rice plants was decreased by applying potassium or clay minerals such as zeolite and vermiculite. The obtained results indicated that high concentrations of radiocesium in rice are potentially a result of the low exchangeable potassium and sorption sites for Cs in the soils. Application of potassium fertilizer and clay minerals should provide an effective countermeasure for reducing radiocesium uptake by plants. Radiocesium-enriched water produced by leaching contaminated leaf litter was used to irrigate rice plants in the cultivation experiments. The results indicated that the radiocesium concentrations in rice plants increased when the radiocesium-enriched water was applied to the potted rice plants. This indicated the possibility that the radiocesium levels in brown rice will increase if the nuclide is transported with water into the rice paddy fields from surrounding forests.


Yasutaka T.,Japan National Institute of Advanced Industrial Science and Technology | Kawamoto T.,Japan National Institute of Advanced Industrial Science and Technology | Kawabe Y.,Japan National Institute of Advanced Industrial Science and Technology | Sato T.,Japan Environment Science Corporation | And 4 more authors.
Journal of Nuclear Science and Technology | Year: 2013

We developed a rapid method for concentrating and measuring radiocesium (134Cs and 137Cs) dissolved in fresh water using nonwoven fabric impregnated with Prussian blue (PB) as a radiocesium absorber in combination with gamma-ray spectrometry using a germanium (Ge) detector. Utilizing this method, dissolved radiocesium in a 20-100 L freshwater sample could be concentrated within a period of 20-60 min by passing the sample through 10-12 columns, connected in series, that had been fitted with nonwoven fabric disks impregnated with PB. Laboratory tests using water samples containing known amounts of radiocesium confirmed that the overall recovery rate of the isotope was 100%-108%, and that the first six columns recovered 84%-97% of the isotope. The detection limit of this method was determined to be 0.002 Bq/L with a sample of 100 L and measurement time of 43,200 s. In comparison with traditional methods using ion-exchange resin, co-precipitation with ammonium phosphomolybdate, etc., our method has the advantages of reduced cost and a significantly shorter concentration time. Since water samples can be treated in short periods of time, it is now possible to conduct radiocesium pre-concentration in situ, thus eliminating the need to transport large-volume water samples to laboratories. © 2013 Taylor and Francis Group, LLC.

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